Using in-line styles with JavaFX ScrollPane - javafx

I'm trying to style a ScrollPane using the inline setStyle() method, but it have no effect on the ScrollPane colors. I've searched SO for examples but none of them were in-line.
sp = new ScrollPane();
String css;
css = ".scroll-pane {-fx-background-color: black;}\n"+
".scroll-pane > .corner {\n" +
" -fx-background-color: black;\n"+
"}\n"+
".scroll-bar:horizontal.track,\n"+
".scroll-bar:vertical.track\n"+
"{\n"+
" -fx-background-color: black;\n"+
" -fx-border-color: black;\n"+
" -fx-background-radius: 0em;\n"+
"}";
System.out.println(css);
sp.setStyle(css);
There is any error on the inline css String?

You can't use selectors in inline styles. You just provide rules that are applied directly to the node (sp in this case). So there is no way to apply an inline style to child nodes, or apply it to pseudoclasses in the way you are trying here.
You could, in theory, do what you are trying to do here with something like
sp.setStyle("-fx-background-color: black;");
sp.lookup(".corner").setStyle("-fx-background-color: black;");
For the pseudoclasses :horizontal and :vertical you would need to register a listener with sp.getPseudoClassStates(). In that listener, you would do a lookup for ".track" and set the style for the track depending on whether or not the set of pseudoclass states contained horizontal and/or vertical.
Obviously this gets prohibitively complex and unmaintainable quickly. You should use an external CSS file for this.

Related

Different behavior of Text and Labeled controls in combination with css

I am working on a Javafx application and I tried to add some Labels, Buttons and Texts, which resizes when the user resizing the Scene. All Nodes are inside a VBox, which itself is inside a StackPane.
My test application:
public class Test extends Application
{
public static void main(String[] args)
{
launch(args);
}
#Override
public void start(final Stage primaryStage)
{
StackPane pane = new StackPane();
VBox box = new VBox();
box.setAlignment(Pos.CENTER);
Label l = new Label("Label");
Text t = new Text("Text");
t.getStyleClass().add("test");
Button b = new Button("Button");
pane.heightProperty().addListener(listener ->
{
double h = pane.getHeight()/5;
l.setFont(Font.font(l.getFont().getFamily(), h));
t.setFont(Font.font(t.getFont().getFamily(), h));
b.setFont(Font.font(b.getFont().getFamily(), h));
});
box.getChildren().addAll(l, t, b);
pane.getChildren().add(box);
primaryStage.setScene(new Scene(pane));
primaryStage.getScene().getStylesheets().add(Path.of("test.css").toUri().toString());
primaryStage.show();
}
}
If I resize the Stage it works as expected. But unfortunately only with pure Java code.
Because after adding my css file, the Labeled controls behave different. While the Text elements continue to change in size, the Labels and Buttons does not change their size anymore.
My css file, which does not work:
.label
{
-fx-text-fill: red;
-fx-font-family: impact;
}
.test
{
-fx-fill: red;
-fx-font-family: impact;
-fx-font-size: 2em;
}
.button
{
-fx-text-fill: red;
-fx-font-size: 2em;
}
I asked myself what I did wrong and have tested different css states. I found out, when I omit font values in css it works, otherwise it does not. Therewhile it does not matter which font value occurs, only one font value is required to miss the behavior.
My css file, which works:
.label
{
-fx-text-fill: red;
//-fx-font-family: impact;
}
.test
{
-fx-fill: red;
-fx-font-family: impact;
-fx-font-size: 2em;
}
.button
{
-fx-text-fill: red;
//-fx-font-size: 2em;
}
1. Question: -has changed, see below-
Do I missunderstand something about css and Javafx, or did I something wrong in my css file or is there a bug?
2. Question: -solved-
Have I to put the font values with java code or is there an other way to add the font?
Thank You for helping!
Update
As recommended I have studying the follow guide:
https://openjfx.io/javadoc/14/javafx.graphics/javafx/scene/doc-files/cssref.html
The JavaFX CSS implementation applies the following order of precedence:
The implementation allows designers to style an application by using style sheets to override property values set from code. For example, a call to rectangle.setFill(Color.YELLOW) can be overridden by an inline‑style or a style from an author stylesheet. This has implications for the cascade; particularly, when does a style from a style sheet override a value set from code? The JavaFX CSS implementation applies the following order of precedence: a style from a user agent style sheet has lower priority than a value set from code, which has lower priority than a Scene or Parent style sheet. Inline styles have highest precedence. Style sheets from a Parent instance are considered to be more specific than those styles from Scene style sheets.
In my case this means, I will use the inline style to make it proper.
thus the 2. Question is solved
But, because of Parent style sheet > value set from code, it also means, all Nodes are not allowed to change theire size, even the Text Node.
Therefore I changed my 1. Question to:
Why does the JavaFX CSS order of precedence differ between Text and Controls
Question 1:
It's not a bug, it's a conflict of priorities. .setFont() has a lower priority than that CSS. Just replace .setFont() to .setStyle() and sample will work as you planned:
l.setStyle("-fx-font-size:" + h + ";");
t.setStyle("-fx-font-size:" + h + ";");
b.setStyle("-fx-font-size:" + h + ";");
Question 2:
Try to keep all about styles in CSS. It's the best practice.

QDockWidget change background color when floating

I have a QDockWidget with a transparent background, but I would like to change the background color or background image when it is floating. It doesn't look like the qt style sheets have a pseudo state to tell you whether or not they are floating, so I'd like to know: is this possible to do?
Found the solution. Add the following connection in the code:
connect(knobDock, &QDockWidget::topLevelChanged, [&] (bool isFloating)
{
if (isFloating)
{
setAttribute(Qt::WA_TranslucentBackground, false);
setAttribute(Qt::WA_NoSystemBackground, false);
}
});
This will cause the dock widgetto use whatever background is specified in the stylesheet when the dock is floating, but it will be transparent (i.e. show the mainwindow background) when it's docked.
You can use custom properties to do this.
Thanks #phyatt for link to Dynamic Properties and Stylesheets.
To declare custom property in your custom class you can write in .cpp:
setProperty("customPropertyName", 1);
or in .h (don't forget to define and implement used get/set access methods too):
Q_PROPERTY( int customPropertyName, READ getCustomPropertyName, WRITE setCustomPropertyName);
And in your global stylesheet file you can use the state of your custom property as following:
.YourClass[customPropertyName="1"] {
background-color: transparent;
}
.YourClass[customPropertyName="2"] {
background-color: black;
}
Also it's needed to reload stylesheet of the object instance after your set new property value, because stylesheets are not recalculated automatically:
object->style()->unpolish(tstFrame);
object->style()->polish(tstFrame);
object->update();
or:
object->setStyleSheet("/* */");

Qt Style Sheet - Different styles for same type widgets

I need to assign different styles for the same typed widget instances. Specially for QActions. Following style sheet sets QActions' background images, actualy tool buttons'.
QToolButton
{
background-image: url(bg.png);
}
But I need to assign different backgrounds for tool buttons like this.
QToolButton::actClose
{
background-image: url(close.png);
}
QToolButton::actOpen
{
background-image: url(open.png);
}
Is there any easy way like this or is it not possible?
You can set object name for instances of QToolButton
QToolButton *button = new QToolButton;
button->setObjectName("firstButton");
button = new QToolButton;
button->setObjectName("secondButton");
and next use them in Style Sheet
QToolButton#firstButton
{
background-color: gray
}
QToolButton#secondButton
{
background-color: red
}
It helps if you can post c++ code that creates the QToolButton and associates with QActions.
Cite from QToolBar's reference "Toolbar buttons are added by adding actions, using addAction() or insertAction(). " and "QWidget * QToolBar widgetForAction (QAction *action )const
Returns the widget associated with the specified action."
So if you are creating QToolBar and call QToolBar::addAction(QAction*) to fill it, it is possible to get pointer to the tool buttons. Try QToolBar::widgetForAction(), and call setObjectName("") and Blueman's method can be applied.
while applying Style Sheet to widgets, "#" is used after class name to specify object name, ":" is used after className of objectName indicating the object's status such like "enabled", "::" is used to specify the subcontrols such as "ListView::Item", unfortunately QAction is neither of QToolBar.

qt mousemoveEvent (involved with qss)

I have a widget class 'BlockWidget' subclass of QLabel, in the ctor I set its qss qss_1, and I want animated effect that when the mouse move on it, it will change its background-color, so I set its qss qss_2, but it seems not working... My code like this:
BlockWidget::BlockWidget(const QString &objname)
{
this->setObjectName(objname);
setAlignment(Qt::AlignCenter);
setStyleSheet(tr("BlockWidget#%1{color:white; background-color: gray; font-size:18px;"
"font-family:'Consolas';}").arg(objectName()));
}
void BlockWidget::mouseMoveEvent(QMouseEvent *ev)
{
setStyleSheet(tr("BlockWidget#%1{color:white; background-color: blue; font-size:18px;"
"font-family:'Consolas';}").arg(objectName()));
repaint();
}
And I have a mainwindow, I instantiated 81 instances of BlockWidget. when my mouse move to one of them, nothing happened. but if I click on it some times, it do change its qss style(its background turns blue)
As stated by the documentation, mouse move events are only sent when you click, drag or release the buttons, if mouse tracking isn't enabled for the widget.
You can detect the mouse entering and leaving the labels by redefining QWidget::enterEvent and QWidget::leaveEvent in your BlockWidget class.
Or you can simply use the :hover QSS pseudo-state without having to redefine any mouse related function:
setStyleSheet("BlockWidget {"
" color:white;"
" background-color: gray;"
" font-size:18px;"
" font-family:'Consolas';"
"}"
"BlockWidget:hover {"
" background-color: blue;"
"}");
PS:
According to Qt style sheet documentation, QLabel doesn't support the :hover pseudo-state, however changing the background or the borders seems to be working fine.
Since your BlockWidget widgets don't have themselves BlockWidget children, and because you set the stylesheet individually to all of them, it should be safe to omit the object name from the QSS selector.
You must enable mouse tracking for your widget http://qt-project.org/doc/qt-4.8/qwidget.html#mouseTracking-prop

Property selectors in QT CSS

I have a tree widget that I'm using for a user/room concept. How can I style the rooms independently from the users in the rooms? I'm assuming it has something to do with QT's property selector in CSS? I would like to be able to do this:
QTreeView::item[isUser="true"] { background: blue; }
QTreeView::item[isRoom="true"] { background: red; }
Since the items in a model are not QObjects (nor QWidgets), you will not be able to add a property to the item, or style them with stylesheets.
I have two suggestions for doing what you want to do :
1) (C++ only) Attach your QTreeView to a QStandardItemModel, and when you add items as QStandardItem objects, you can call QStandardItem::setBackground() with either Qt::blue or Qt::red depending of whether the item is a room or a user.
2) (C++ and CSS) Define a QStyledItemDelegate that you attach to your QTreeView. In your reimplementation of QStyledItemDelegate::paint() method, use a QLabel to display the content of the item, then set a property on that QLabel. You will then be able to use a stylesheet to customize the look of the label :
QLabel[isUser="true"] { background: blue; }
QLabel[isRoom="true"] { background: red; }
I was able to accomplish what I needed by creating a label, using the setProperty method on that label, and then using the setItemWidget function to attach that QLabel to the appropriate QTreeWidgetItem. So I wouldn't be "styling the QTreeWidgetItem", but rather styling the QLabel that was overlayed on top of the QTreeWidgetItem. The following example sets my topLevelItem in the QTreeWidget to be ready to be styled as a room:
QTreeWidgetItem *topItem = ui->treeWidget->topLevelItem(0);
currentLabel = new QLabel;
currentLabel->setProperty("room",true);
currentLabel->setText(QString("Room Lobby"));
ui->treeWidget->setItemWidget(topItem,0,currentLabel);`
I can then select it in the stylesheet with
QLabel[room="true"] { background: red; }

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